Intelligence and Miscellaneous Articles. 543 



Leyden jar, the well-known mixture of sulphur and minium. 

 After the discharge of the condensers those figures can no longer be 

 distinguished ; for the electrified zones more or less completely de- 

 stroy one another at the very instant. 



9. "When the Franklin's square has its coatings unequal, the 

 neutral zone on the side of the smaller coating, as well as the 

 electrified zone, increases in extent at the moment of the discharge, 

 at least in certain cases. 



10. In studying by this method some squares of glass with un- 

 equal coatings, or, better of ebonite, with coatings unequal or equal, 

 I have observed that after they had been discharged as usual, the 

 coatings were found to be charged with the opposite electricity to 

 that which they had originally. 



Perhaps this method of investigation, modified and extended, may 

 in the future offer us useful indications respecting the inversion of 

 discharges, the influence of the insulators and varnishes made use 

 of in condensers, aud the different ways in which the two electri- 

 cities spread over the insulators — questions to all of which I hope, 

 some day, to return. — Comptes Rendus de V Academic des Sciences, 

 April 4, 1881, t. xcii. pp. 872-874. 



THE SECULAR INEQUALITIES IN TERRESTRIAL CLIMATES DE- 

 PENDING ON THE PERIHELION LONGITUDE AND ECCENTRICITY 

 OF THE EARTH'S ORBIT. 



A paper on this subject, by the Rev. Dr. Haughton, of Trinity 

 College, Dublin, was read before the Royal Society on February 24 

 last. Dr. Haughton shows that the two inequalities in question 

 depend upon terrestrial radiation only, and in no way upon sun- 

 heat. 



Having noticed that the hottest and coldest time of day follows 

 noon and midnight by an interval often considerable, and in like 

 manner that the hottest and coldest days in the year follow mid- 

 summer and midwinter * by an interval often of many days, Dr. 

 Haughton saw in these facts a close analogy with the diurnal tides, 

 which follow the sun or moon's meridian passage by an interval of 

 some hours. 



Dr. Haughton was thus led to solve the differential equation on 

 which the problem depends, by assuming an expression similar to 

 those so well known and so long employed in the mathematical 

 discussion of the tides of the ocean. 



The result fully justified the assumption of expressions similar to 

 diurnal tidal expressions ; for when the differential equation is in- 

 tegrated for a day and summed for a year, all the periodic terms 

 disappear, and nothing is left but terms depending on the perihe- 

 lion longitude and eccentricity, which represent the exact mathe- 

 matical expression of the two inequalities first noticed by Adhcmar 

 and Croll. 



* In the British Islands January 15 is reckoned the time of maximum 

 cold, which is twenty-four clays alter midwinter. 



